1. Field of the Invention
The present invention relates to a method of setting a tracing zone in a contour tracing in which a surface of a model is traced by tracing a contour thereof so as to machine a workpiece, and more particularly, to a method of setting a tracing zone in which the tracing zone is set by using a plurality of folded lines.
2. Description of the Related
Tracing machining in which a model is traced so as to machine a workpiece is widely used, as the workpiece can be machined without preparing a machining program of the model. Particularly, contour tracing is useful because a free curved surface, which can not be enciphered, can be easily machined thereby.
Not all of the surfaces of the model are needed for general tracing, only zones which are a part thereof as effective curved surfaces. Therefore, usually a zone for the contour tracing is set for the machining.
Contour tracing zones, however, are usually set by straight lines in parallel to the X-axis or the Y-axis, and thus, unless the contour tracing zone is within a rectangle on the X-Y plane, unnecessary zones are machined by the contour tracing, which results in a prolonged machining time and a reduced life of the tools.